With increasing government demands on emission control systems and fuel mileage concerns, the power plant of a vehicle has become a high tech engineering marvel. This, in turn, means that the automotive technician is faced with increasing difficulties of diagnosing and repairing complicated systems. Repairs must be completed in a timely manner which has become a problem for many automotive repair shops.
The modern vehicle (1996 and later models) has a number of microprocessors including one programmed to control the running parameters of the power plant (i.e., the powertrain control module). The data from this microprocessor provides the skilled technician with information that is needed in order to make diagnostic decisions about the power plant. However, as the power plant systems become more complicated, more data and a better understanding of such data is needed in order to make accurate diagnostic decisions, thus making it more difficult for technicians to see a problem when it occurs. Even if available data is saved, a technician may overlook important information and can misdiagnose the system.